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preface This article mainly explains the classic usage scenarios of Zookeeper, the use of Zookeeper native client and Apache cursor open source client, and the configuration of Zookeeper cluster. Zookeeper mainly includes: Distributed configuration centerDistributed registryDistributed lockDistributed queueCluster electionDistributed ba ...

#Unified identity management platform IAM Many enterprises have multiple office systems. Accounts, passwords, roles and permissions need to be set separately and cannot be managed uniformly. I think the unified identity authentication management system IAM has the following three advantages: Establish a unified user management, identity rati ...

This article is excerpted from the Flyweight Pattern of "design patterns should be learned in this way"1 story backgroundBecause a programmer changed a method parameter in the production environment and changed the int type to Integer type, because money was involved, the company suffered heavy losses and the programmer was dismissed. ...

Reproduced in https://www.jianshu.com/p/d83623eb56dc 1, System functional requirements Add contact: add a new contact to the address book. The information includes (name, gender, age, contact number, home address) and records up to 1000 people Show contacts: displays all contact information in the address book Find contact: delete the specified ...

re.match() find one from scratch re.search() found one** re.findall() find all **Returns a list. If there is no, it is an empty list re.findall('\d','chuan1zhi2')   The result is['1','2'] re.sub() replace re.sub('\d','_','chuan1zhi2')   The result is['chuan_zhi_'] Re.compile** Returns a model p with the same method as re, but with dif ...

This article is excerpted from the Flyweight Pattern of "design patterns should be learned in this way" 1 story background Because a programmer changed a method parameter in the production environment and changed the int type to Integer type, because money was involved, the company suffered heavy losses and the programmer was dism ...

background At the beginning of the article, let's talk about the NPE problem. The NPE problem is the NullPointerException we often encounter in development. Suppose we have two classes, and their UML class diagram is shown in the figure below. In this case, there is the following code user.getAddress().getProvince(); In this way, when the u ...

1 what is JUC 1.1 introduction to JUC In Java, the thread part is a key point. The JUC mentioned in this article is also about threads. JUC is short for Java. Util. Concurrent toolkit. This is a toolkit for processing threads. JDK 1.5 began to appear. 1.2 processes and threads Process is a running activity of a computer program on a data s ...

The life cycle of a Bean can be divided into four steps Bean instantiationBean attribute assignmentBean initializationDestroy In traditional Java applications, the life cycle of a Bean is very simple. Instantiate a Bean using the Java keyword new, and then the Bean can be used. Once the Bean is no longer used, Java automatically garbage colle ...

I believe you may have such a business requirement when you are working on a project: the data displayed on the page or interface shall be kept to two decimal places. Then, this article will share with you several ways of using Java to retain two decimal places. The article gives a detailed example code, which is very helpful for your learning ...